One of the more conventional types of paint spraying systems incorporates a painting booth or room through which articles to be painted are moved by a conveyor. A human operator stands close to the articles with a paint spraying unit and sprays the articles as they move adjacent to him. The booth has an open floor so that particles of paint not landing on the article may pass through the floor to a lower liquid where they are collected, either to be reused or to be disposed of. In order to protect the operator that is spraying the articles, there is provided an air system having very large volumetric capacity which moves air across the area where the operator is standing and prevents paint particles and solvent from remaining in the area. Normally, the operator is provided with a small filter mask that prevents incidental paint particles from entering his lungs and respiratory system. Generally, the amount of air passing through the area is controlled by government regulations or through normal standards of safety. Solvent-laden air leaving the booth is moved to exhaust chimneys which discharge the air and its solvents externally of the building containing the booth.
Associated with paint spraying units are immersion-type washer units through which the articles to be painted are immersed and cleansed prior to their reaching the painting booth. This is done for the purpose of removing oil and other foreign matter from the surfaces of the respective articles, thereby insuring uniform painting. Normally, the liquid contained in the washer or immersion tank is heated, conventionally by oil or gas burners. Exhaust from the burners is discharged through conventional stacks to the atmosphere. The exhaust from the burners is relatively clean and there is normally no objection to this type of exhaust.
One of the problems with the above described type of paint spraying systems is that the air moving through the paint booth that is exhausted externally of the building becomes solvent-laden and particle-laden and creates environmental problems. As the governmental environmental restrictions become more strict, it is possible that in the future such emission of the solvent-laden air will be prohibited in its entirety. Even today, the type and quality of such discharge requires considerable filtering and cleaning.
A second problem that is created by this system of paint spraying is that there is required a large volume of air that must continuously move past the human operator spraying the articles. Not only does this require energy for moving the air, but it necessitates a tremendous amount of energy for heating the air prior to its passing adjacent the operator. This is a problem particularly in northern areas and particularly during the colder weather when all air taken from the outside must be heated. In some instances there is required as much as 80,000 cfm of air for each human in the spraying booth. In such instances, the energy used to heat this air may far exceed all other costs in the spraying operation.